Various methods and apparatus for mixing dry particles or dry bulk materials, such as polyelectrolytes and the like, with a wetting agent, such as water, have been proposed. However, all such methods and apparatus have had disadvantages, particularly in failing to provide for the adequate and complete dissolution of the dry particles into the wetting agent to prepare a homogenous liquid solution. It is a well-known characteristic of dry powders and like dry particles that agglomeration occurs when such powders or particles initially come into contact with a wetting agent. These agglomerations limit the access of the wetting agent to the particles located on the interior of the agglomerations and thus preclude the complete dissolution of all of the particles so that a homogenous liquid solution can be prepared.